dry vent to wet vent

I hope someone can help. I'm remodeling an apartment building 5 stories. each set of 2 apartments bathrooms are lined up next to eachother and have a dryvent running up next to the sewage/sink line. the dryvent taps into the line on every floor but is dry. We want to add a kitchen next to the bathroom and use the dryvent to run kitchen sinks. the dryvents are copper pipe maybe 3" or more. would switching the dryvent to a wetvent by a problem. if so could those cheater valves (air in) be used on the kitchen sinks to get air back into the line at each sink.

I dont personally see why we would need aload of totally dryvents. i would assume taping just a sink into them wouldnt be an issue since we still have plenty space for gas to escape and air is still behind water and everything.

I hope someone can help me. this is in new brunswick canada. i believe every 2 bathrooms are hooked up to its own 3"+ dryvent and it connected to each set of 2 bathrooms all the way up through the 5 floors. the building is thick concrete and running a new drain line through the building all over the place is next to impossible so i need a way to use this dry vent to drain the new kitchen sinks. the kitchen sinks would literraly be on the other side of the drywall from the dryvent and would connect straight into it. its as close to the line as is humanly possible if that matters.

I hope someone can help maybe somone has some experience with this commercial setting or something.